爆炸荷载作用下UHPC板的弯曲损伤评估  

Flexural damage assessment for UHPC panels under blast loadings

作　　者：苏琼 程月华 吴昊 SU Qiong;CHENG Yuehua;WU Hao(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《爆炸与冲击》2023年第12期123-138,共16页Explosion and Shock Waves

基　　金：国家自然科学基金(52078379)。

摘　　要：为构建爆炸荷载作用下超高性能混凝土(UHPC)板弯曲损伤等级评估的p-I(压力-冲量)曲线:采用条带法进行截面分析,建立了考虑UHPC材料拉/压软化和塑性铰影响的UHPC简支单向板的非线性抗力方程和等效单自由度(ESDOF)理论模型;通过与六炮次爆炸实验中UHPC板的挠度时程,以及UFC 3-340-02和FHWA规范推荐方法的计算结果对比,验证了本文理论模型的可靠性;基于验证的ESDOF模型,构建了评估UHPC板的不同弯曲损伤等级的p-I曲线并开展了参数影响分析,提出并验证了UHPC板弯曲损伤评估的p-I曲线经验公式。结果表明:提高混凝土强度等级和钢筋屈服强度、增加受拉钢筋配筋率和板厚,以及减小净跨均可提升UHPC板的抗爆性能。To establish the p-I(pressure-impulse)diagram for flexural damage assessment of ultra-high performance concrete(UHPC)panels under blast loadings,cross-sectional analysis using the strip method was performed to establish the moment curvature relationship for simply supported one-way UHPC panels.This process involved considering the tensile/compressive softening of UHPC through the utilization of material constitutive models with softening properties and describing the strain rate effect of UHPC and reinforcement with the dynamic increase factor(DIF)that varies according to different strip layers.Subsequently,the nonlinear resistance function considering the effect of plastic hinge was developed,based on the moment curvature relationship and a simplified half-span symmetric beam model.Then,an equivalent single degree of freedom(ESDOF)theoretical model,adopting the nonlinear resistance function,was established and employed to predict the deflection-time histories of UHPC panels under explosions.The reliability of the above theoretical model was verified by comparing the predicted results with the deflection time histories of test UHPC panels in six shots of explosion tests.Additionally,the superiority of the proposed ESDOF model was proved by comparing with the corresponding calculation results obtained from the recommended methods using bilinear ideal elastic-plastic resistance functions based on the UFC 3-340-02 and FHWA codes.Furthermore,based on the verified ESDOF model,p-I diagrams for evaluating the flexural damage level of UHPC panels were established and parametric analysis was carried out.The results indicate that increasing the concrete strength grade,yield strength of reinforcement,tensile reinforcement ratio,and panel thickness,while reducing the clear span,are beneficial for the blast-resistant performance of UHPC panels.Finally,empirical formulae for p-I diagrams,taking into consideration the abovementioned influencing factors,were proposed and verified for assessing the flexural damage of UHPC panels.

关 键 词：超高性能混凝土 爆炸荷载 等效单自由度 p-I曲线 损伤评估 

分 类 号：O389[理学—流体力学] TU375.2[理学—力学]